This study was conducted on 25 male buffalo-calves, with age range, 6-7 months old (158 - 165 kg bwt), belonged to a private farm in Beni-Suef governorate. The animals were divided into three groups; control group (5 buffalo-calves) received probiotic-free ration, Group I and Group II (10 buffalo-calves in each). Buffalo-calves in groups I and II were orally administered with 15 and 25 g (Biovet®)/animal/day with respectively. The experiment lasted for 84 days. The effect of probiotic (Biovet®) supplementation on clinical, hematological and biochemical parameters as well as on the body weight gain in growing buffalo-calves were investigated. Hemoglobin concentrations, packed cell volume (PCV %), erythrocyte counts (RBCs) and total leucocytes counts (WBCs) of group I, and II revealed insignificant alterations comparing to control group. Insignificant variations of aspertate aminotransferase activities (AST), alanine aminotransferase activities (ALT), albumin, globulin, urea and creatinine levels of groups I and II were also recorded. The activities of alkaline phosphatase (ALP) in groups I and II buffalo-calves were significantly increased comparing to that in control animals. The levels of the total protein and the glucose levels in the probiotic-treated buffalo-calves increased significantly (P<0.05) comparing to that in control animals starting from 28th and 42th day till the end of the experiment respectively. The levels of triglycerides, cholesterol, HDL-cholesterol decreased insignificantly in (Biovet®) whereas LDL-cholesterol levels significantly decreased (P<0.05) in treated groups comparing to that in control animals. The T3 and T4 concentrations and body weight gain in probiotic-treated buffalo-calves significantly increased (P<0.05) in comparison to control group. The study declared that the probiotic (Biovet®) has obvious effect on body weight gain in buffalo-calves without any deleterious effect on animal health.